The world of porn wasn't the only industry rocked by Wednesday's FBI raid on the Center City adult-entertainment conglomerate National A-1 Advertising Inc.

The people who track, sell, buy and trade toll-free numbers were atwitter yesterday as news spread of the sweep, which affected not only businesses such as a phone-sex line and porn websites, but subsidiaries that buy up toll-free numbers.

And National A-1 does it aggressively, said Bill Quimby, founder of Tollfreenumbers.com.

"They're more mafia-like than any organization I've seen or heard," said Quimby, a national expert on the industry.

"They forge paperwork, yank numbers; they don't care what other people think about them."

National A-1, on 7th Street near Chestnut, owns six "responsible organizations," or "resporgs," which are allowed to purchase toll-free numbers. The six resporgs combined control 1.9 million of the 7.8 million toll-free numbers that are available, Quimby said.

They are "playing monopoly with vanity [toll-free] numbers, and they make money along the way," Quimby said.

The resporgs - all six are referred to as "PrimeTel" even though they have separate official names - buy but don't sell, and are sitting on about $1 billion worth of phone numbers, Quimby added.

PrimeTel is banking on the public punching in a wrong number.

There are "isolated stories in the news media that pop up every once in a while that a number that belonged to a nice church or a White House press briefing now belongs to a phone-sex company," Quimby said.

"Each story imagines that this is just a coincidence. It's not a coincidence; that's their business to generate wrong numbers."

A few years ago, Medicare hotlines in at least six states, including Pennsylvania, were swooped up by National A-1, and callers were redirected to phone-sex lines.

A former National A-1 phone-sex supervisor who spoke on the condition of anonymity said that the company's CEO, Richard Cohen, "was a good guy" but that the office atmosphere was "shady. It was definitely shady."

The conglomerate had been known as National Telephone Enterprises for some time, and then suddenly it wasn't, he said.

" 'If anybody asks about it [NTE], you don't know anything,' " the employee said he had been told by a manager. And there were other issues related to the communications industry.

"This thing they used to do with these telephone lines in Bell South areas, like Florida, anywhere in the South, they had these . . . numbers like 2-1-1 that would take you to local chatting lines," he said.

Unknowing people with children who may have played with the phone would call to inquire about mysterious charges that would show up on their phone bills, the employee said.

Quimby said that it's the PrimeTel way. "If the amount of money you made was based on the amount of wrong numbers you received, and the amount of wrong numbers you received was based on good toll-free numbers you had, how many toll-free numbers would you want?" he said.

Jan Uzzo, a New York businessman who says PrimeTel took a toll-free phone number he controlled, called the news "wonderful."

"I think a company like PrimeTel deserves everything that happens to them," Uzzo told the Daily News. "They have been skirting the law - nobody has been policing them."

One lawyer who represented Cohen and National A-1 Advertising in a previous civil case declined to comment, and another lawyer who represented them in a different civil matter could not be reached for comment.

FBI agents again visited PrimeTel and the rest of National A-1 Advertising yesterday, and the building where it occupies six floors was closed to the public.

A Pennsylvania state trooper was at the front door along with another plainclothes law-enforcement official.

National A-1's various websites, which were down most of Wednesday, appeared to be up and running yesterday.

Emily Guendelsberger and staff writer Michael Hinkelman contributed to this report.